FF cameras give you a wider envelope of shooting conditions - for example a wider choice of DOF (depending on the lens, of course) and lighting conditions under which you can get the same shot.

No to all of the above, answer the question? dof blur is all acheivable now in post, the envelope you talk about is in your head.

You can level the playing field a bit with software blurring, but it's very difficult to use for some kinds of subjects such as the one below and it can result in some very unnatural looking edges.

And none of that says anything about the ability of FF cameras to capture lower-noise images in poor lighting conditions.

M43 is perfectly adequate for many people and it certainly sounds like you're very happy with it - I'm glad. It's perfectly adequate for me, too. But to imply that what's good enough for you and me must therefore be good enough for everyone is simply wrong.